1. Field of the Invention
The present invention is directed generally to a method for determining the concentration of a selected ingredient in complete animal feeds and is more particularly concerned with a novel method for performing such analyses utilizing gentian violet as a tracer substance.
2. Prior Art
The animals, cattle, swine and poultry, that are used most commonly today for production of meat and dairy products are specially bred and raised descendants from animals that once lived naturally in the environment. In recent years, the methods by which such livestock are raised particularly for meat production, have advanced very rapidly. The methods and the associated equipment utilized today have achieved a considerable level of sophistication and have, concomitantly, caused the removal of the animals from their natural environment. In particular, the animals are confined generally to very small areas throughout their growth periods. This forced confinement has both benefits and drawbacks. The benefits are that the animals are prevented from using their muscles in such a way to cause the meat produced to be stringy and tough. On the other side, the animals, by being out of their natural environments, must be fed a fortified diet to compensate for the absence of many feed elements formerly provided within their natural environments.
The general intent of the animal production methods now used is to cause the animals to grow to a marketable size as rapidly as possible. Or, the case of those producing dairy products, to mature rapidly and provide a maximum yield for as long a period as possible. As a result, the industries that raise the livestock and those that provide support to them have become highly specialized. Within the livestock industry, this is achieved through careful breeding and adjustment of the artifical environment. The breeding process has tended to create specialized strains of animals that develop rapidly and put on weight appropriate to quality meats. In the support area, careful balancing of the nutrients furnished to the grower for the animal, particularly those nutrients that do not occur in sufficient supply in naturally grown feeds. As a result, the growth periods for the animals to be ready for market, have been reduced significantly.
The diet fortification materials are added to the diet by mixing them with the more conventional feed provided to the animals which provides conventional protein and energy sources. Modern feed formulations require careful and precise fortification formulation to realize fully the increased growth and production capabilities of today's higher producing animal and poultry strains. In the artificial environments being used, failure to achieve minimum standards of feed fortifications can be both wasteful and costly. The diet fortification materials, which are commonly denominated "microingredients", include vitamins, minerals, antibiotics, preventative and/or therapeutic drugs, antioxidants, supplemental amino acids, enzymes, preservatives, flavors, ingredients that are commonly called "unidentified growth factor sources" and other elements that are found to be necessary in particular applications. Poor uniformity, particularly of the diet fortification materials, within the feedstuff can result in inadequate nutritional intake by the animals or possibly even marginally toxic levels of certain microingredients being located in parts of the feed. Such nonuniformities are generally not fatal; however, regardless of whether they represent deficiencies or excesses, they can be economically harmful to the producer.
The microingredients that are added to the animal feed materials are generally prepared as a "premix" for later addition to the feed. The premix is of a particle size that is much smaller than the grain, soybean and other conventional nutrient materials. In order that the animals receive proper mixtures of the ingredients, considerable care must be employed to insure that adequate mixing is accomplished and that nothing occurs thereafter to cause separation of the various ingredients. If a sufficient separation occurs such that the microingredients' concentration in the feedstuff varies significantly from the intended levels, the growth rates for the animals will almost certainly decline.
Problems in homogeneity of the mixed fortified feed can occur from a wide variety of causes. For example, if equipment being utilized for mixing and blending the various feed materials becomes worn, a distinct lack in homogeneity may and probably will gradually develop. For example, the most commonly used type of feed blending equipment is the horizontal ribbon blender. In these blenders, wear can and usually does occur on the mixing blade which can result in spaces of as much as an inch. In such spaces, the feed tends to be static and to avoid mixing.
Moreover, and perhaps more importantly, the automated equipment that is utilized conventionally for mixing the ingredients may, and occasionally does, malfunction for short periods of time. This is a particular problem in measuring the microingredients into the feed. One standard measure of the premix of fortification ingredients that is utilized is about five pounds per ton of feed. Clearly, minor variances in the rate at which the microingredients are dispensed into the feed can cause wide variations in the resultant concentration of those ingredients. For example, if the valve through which the premix is added to the feed is opened for five seconds to allow five pounds of premix to pass into the feed, a variation of half a second resulting from an error in timing or a sticking during the closing or opening of the valve can cause a ten percent variation in the concentration of premix in the ultimate feed.
Even if the original mixing of ingredients occurs properly, it is far from a certainty that the microingredients will remain uniformly mixed until the feed is dispensed to the animals. The particle size of the microingredients is considerably smaller than that of the more conventional nutrients; therefore, during handling of bulk feeds, the ingredients often tend to separate, allowing the larger particles (the nutrients) to sink and the smaller ones (the microingredients) to rise, thereby destroying the homogeneity. This may occur, for example, when the feed is removed by auger from the mixing apparatus to a storage facility.
A more critical problem in the handling occurs when the mixed bulk feed is transported from the storage facility to the farm for feeding to the livestock. The feed is transported in bulk by truck in most instances. Such trips often require travel of forty miles or more, often over less-than-ideal road conditions. The vibration that is caused within the truck in turn will on occasion be sufficient to again cause the particles to separate according to size.
At present, there are no means available for rapidly and inexpensively checking the concentration and/or homogeneity of microingredients in a sample of the mixed feed without furnishing that sample to a testing laboratory, as the typical farm cannot afford the sophisticated testing equipment nor has the technical know-how to use it. As is apparent, such testing procedures are wholly inadequate to insure proper levels of microingredients in mixed feed, either at the feed market, the storage facility or at the farm. Therefore, wide variations in feed mixtures are often fed to livestock without any knowledge being available to the farmer that the feed is, in fact, incorrect, thereby lowering the efficacy of the feeding process and damaging the farmer economically.